Douglas was born on March 26, 1892 in the small town of Salem, Massachusetts. When he was four, his mother died of natural causes and his father remarried. His father was an abusive husband and his stepmother, unable to obtain a divorce, left her husband and took Douglas and his older brother to Onawa, Maine in Piscataquis County, where her brother and uncle had built a resort in the woods.

Douglas graduated from Bowdoin College with a Phi Beta Kappa key in 1913. He then moved on to Columbia University, where he earned a master's degree in 1915 and a Ph.D. in economics in 1921. In 1915, he married Dorothy Wolff, a graduate of Bryn Mawr College who also earned a Ph.D. at Columbia University.

From 1915 to 1920, the Douglases moved six times. Paul studied at Harvard University; taught at the University of Illinois and at Oregon's Reed College, served as a mediator of labor disputes for the Emergency Fleet Corporation of Pennsylvania and taught at University of Washington. When working for the Emergency Fleet Corporation he read John Woolman's journals. When teaching in Seattle, he joined the Religious Society of Friends.

In 1919, Douglas took a job teaching economics at the University of Chicago. In 1921, he met social reformer Jane Addams. Although Douglas enjoyed his job, his wife was unable to obtain a job at the university due to anti-nepotism rules. When she obtained a job at Smith College, she persuaded her husband to move the family to Massachusetts where he taught at the University of Massachusetts Amherst. While at Chicago, Douglas developed (with Charles W. Cobb, a mathematician at Amherst) the Cobb-Douglas production function, an often used production function in neoclassical economics. Douglas soon decided that the situation was untenable and, in 1930, the couple divorced, with Dorothy taking custody of their four children and Douglas returning to Chicago. The following year, Douglas met and married Emily Taft Douglas, daughter of sculptor Lorado Taft and distant cousin of former President William Howard Taft. Emily was a political activist, former actress, and subsequent one-term congresswoman at-large from Illinois (1945—47).

Douglas was listed as a supporter of banking reforms suggested by University of Chigaco economists in 1933 that were later referred to as the "Chicago plan". In 1939, he coauthored with five other notable economists a draft proposal titled A Program for Monetary Reform. The Chicago plan and A Program for Monetary Reform generated much interest and discussion among lawmakers, but the suggested reforms did not result in any new legislation.

As the 1920s drew to a close, Douglas got more involved in politics. He served as an economic advisor to Republican Governor Gifford Pinchot of Pennsylvania and Democratic Governor Franklin D. Roosevelt of New York. Along with Chicago lawyer Harold L. Ickes, he launched a campaign against public utility tycoon Samuel Insull's stock market manipulations. Working with the state legislature, he helped draft laws regulating utilities and establishing old-age pensions and unemployment insurance. By the early 1930s, he was vice chairman of the League for Independent Political Action, a member of the Farmer-Labor Party's national committee, and treasurer of the American Commonwealth Political Federation.

A registered Independent, Douglas felt that the Democratic Party was too corrupt and the Republican Party was too reactionary, views that he expressed in a 1932 book, The Coming of a New Party, in which he called for the creation of a party similar to the British Labour Party. That year, he voted for Socialist candidate Norman Thomas for President of the United States.

After Roosevelt's victory in the election, Douglas, at the recommendation of his friend Harold Ickes, was appointed to serve on the Consumers' Advisory Board of the National Recovery Administration. In 1935, however, the Supreme Court ruled that the Administration was unconstitutional and it was abolished.

That year, Douglas made his first foray into electoral politics, campaigning for the endorsement of the local Republican Party for mayor of Chicago. Although the party endorsed someone else, Douglas continued to work with them to get their candidate elected to the city council from the 5th Ward. A strong Socialist candidate split the reform vote, however, and Democrat James Cusack, a member of the Cook County political machine, was elected.

Four years later, in 1939, Cusack came up for re-election, and Douglas joined a group of reform-minded Independents in attempting to select a suitable challenger. The group decided that Douglas was the best candidate for the position and he was summarily drafted. During the election, Mayor Ed Kelly, a leader of the machine who was in a tough fight for re-election, attempted to shore up his reputation by lending his support to Douglas' campaign. With Kelly's help, and his own dogged campaigning, Douglas managed a narrow victory over Cusack in a runoff election.

A reformer on a council full of machine politicians and grafters, Douglas usually found himself in the minority. His attempts to reform the public education system and lower public transportation fares were met with derision and he typically ended up on the losing end of 49-1 votes. "I have three degrees", Douglas once said after a particularly close-fought rout. "I have been associated with intelligent and intellectual people for many years. Some of these aldermen haven't gone through the fifth grade. But they're the smartest bunch of bastards I ever saw grouped together."

In 1942, Douglas officially joined the Democratic Party and ran for its nomination for the United States Senate. He had the support of a cadre of left-wing activists, but the machine supported the state's at-large Congressman Raymond S. McKeough for the nomination. On the day of the primary, Douglas carried 99 of the state's 102 counties, but McKeough's strong support in Cook County allowed him to win a slim majority. He would go on to lose in the general election to incumbent Republican Senator C. Wayland Brooks.

As alderman, Douglas had worked with Chicago Daily News publisher Frank Knox in fighting corruption in Chicago. Knox, who had been Republican vice-presidential nominee in 1936, had become Secretary of the Navy, thus responsible for both the navy and the Marine Corps.

Shortly after losing the primary, Douglas resigned from the Chicago City Council and, with the aid of Knox enlisted in the United States Marine Corps as a private at the age of 50. (As a member of the 57th Street Meeting of the Quakers, Douglas recognized that joining the Marines was contrary to the traditional testimony of that group against war and offered to resign his membership; the meeting refused to release him. Promoted to corporal, then to sergeant, Douglas was kept stateside, writing training manuals, and giving inspirational speeches to troops. He was told he was "too old to go overseas 'as an enlisted man'". With the aid of Knox, and of Knox assistant Adlai Stevenson, Douglas was commissioned as an officer, and was subsequently sent to the Pacific theater of operations with the 1st Marine Division.

On the second day of the Battle of Peleliu, Captain Douglas finally saw action when his unit waded into the fray. He earned a Bronze Star for carrying ammunition to the front lines under enemy fire and earned his first Purple Heart when he was grazed by shrapnel while carrying flamethrower ammunition to the front lines. In that six week battle, while investigating some random fire shootings, Douglas was shot at as he uncovered a two-foot-wide cave. He then killed the Japanese soldier inside at which point he wondered whether his enemy might be an economics professor from the University of Tokyo.

A few months later, during the Battle of Okinawa, Douglas earned his second Purple Heart. A volunteer rifleman in an infantry platoon, he was helping to carry wounded from 3rd Battalion 5th Marines along the Naha-Shuri line when a burst of machine gun fire tore through his left arm, severing the main nerve and leaving it permanently disabled.

After a thirteen-month stay in the National Naval Medical Center at Bethesda, Maryland, Douglas was given an honorable discharge as a Lieutenant Colonel with full disability pay.

While Douglas had been serving in the Marines, his wife, Emily, had been nominated to run against isolationist Republican Congressman Stephen A. Day, who had succeeded Raymond McKeough. Although she had defeated Day in the 1944 election, a Republican upsurge had unseated her in 1946, the same year that Douglas left the Marines.

Deciding to enter politics once again, Douglas let it be generally known that he wished to seek the office of Governor of Illinois in 1948. Cook County machine boss Jacob Arvey, however, had a different plan. At the time, several scandals had broken out over the machine's activities, and Arvey decided that Douglas, a scholar and war hero with a reputation for incorruptibility, would be the perfect nominee to run against Senator Brooks. Since Brooks was hugely popular in the state and had a large campaign warchest, Arvey decide that there was no danger of Douglas winning.. The top 2/3 of the Illinois Democratic slate for the 1948 election then became Paul Douglas for senator and Adlai Stevenson for governor.

At the outset of the campaign, Douglas' chances looked slim. As a delegate to the 1948 Democratic National Convention, he had tried to draft General Dwight D. Eisenhower for President, calling President Harry S. Truman "incompetent."

Douglas, however, proved to be a tenacious campaigner. He stumped across the state in a Jeep station wagon for the Marshall Plan, civil rights, repeal of the Taft-Hartley Act, more public housing, and more social security programs. During six months of non-stop campaigning, he traveled more than around the state and delivered more than 1,100 speeches. When Senator Brooks refused to debate him, Douglas debated an empty chair, switching from seat to seat as he provided both his own answers and Brooks'.

On Election Day, Douglas won an upset victory, taking 55 percent of the vote and defeating the incumbent by a margin of more than 407,000 votes. Stevenson won the race for governor by a wide margin, but there was no coattails effect from president to senator to governor; President Truman, campaigning for re-election, won the state by a slim 33,600 votes.

As a member of the Senate, Douglas soon earned a reputation as an unconventional liberal, concerned as much with fiscal discipline as with passing the Fair Deal. Although he was a passionate crusader for civil rights (Dr. Martin Luther King, Jr. described him as "the greatest of all the Senators"), Douglas earned fame as an opponent of pork barrel spending. Early in his first term, he grabbed headlines when, magnifying glass and atlas in hand, he strode to the Senate floor and, referring to a pork barrel project for the dredging of a river in Maine, defied anyone to find the river in the atlas. When Maine's Owen Brewster objected, and pointed out the millions of dollars in pork going to Illinois, Douglas offered to cut his state's share by 40%.

Appointed to chair the Joint Economic Committee, Douglas led a series of hard-hitting investigations into fiscal mismanagement in government and appeared on the cover of Time. A profile of him in that issue was entitled "The Making of a Maverick."

As the 1952 presidential election approached, a groundswell of support arose for a Douglas candidacy for President. The National Editorial Association ranked him the second-most-qualified man, after Truman, to receive the Democratic presidential nomination, and a poll of 46 Democratic insiders revealed him to be a favorite for the nomination if Truman stepped aside.

Douglas, however, refused to be considered as a candidate for President, and instead backed the candidacy of Senator Estes Kefauver of Tennessee, a folksy, coonskin cap-wearing populist who had become famous for his televised investigations into organized crime. Douglas stumped across the country for Kefauver and stood next to him at the 1952 Democratic National Convention when Kefauver was defeated by Illinois Governor Adlai Stevenson. Four years later, in 1956, he remained publicly neutral, feeling that openly opposing Stevenson's drive for the nomination and supporting Kefauver would damage his standing with his state party.

In addition to his battles for equal rights for African Americans and less pork barrel spending, Douglas was also known for his fights for environmental protection, public housing, and truth in lending laws. He opposed real estate redlining, but was forced to allow a 1949 provision in a public housing bill making it possible for suburbs to reject low-income housing. He also authored the Consumer Credit Protection Act, a bill that forced lenders to state the terms of a loan in plain language and restricted the ability of lenders to discriminate on the basis of gender, race, or income. Although the bill was not passed during his term of office, it became law in 1968.

During the 1966 election, Douglas, then 74, ran for a fourth term in office against Republican Charles H. Percy, a wealthy businessman. A confluence of events, including Douglas' age, unhappiness within the Democratic Party over his support for the Vietnam War and open housing laws, as well as sympathy for Percy over the recent, unsolved murder of his daughter, caused Douglas to lose the election in an upset.

After losing his seat in the Senate, Douglas taught at the New School, chaired a commission on housing, and wrote books, including an autobiography, In the Fullness of Time.

In the early 1970s, he suffered a stroke and withdrew from public life. On September 24, 1976, he died at his home. He was cremated and his ashes were scattered in Jackson Park near the University of Chicago.

A memorial marker at the Marine Corps training base at Parris Island reads:

DOUGLAS VISITORS CENTERin Memory ofSENATOR PAUL H. DOUGLAS1892 ~ 1976Graduating from Parris Island in 1942 as a 50 year old Private. Mr. Douglas was an inspiration to all. He rose to the rank of Major while serving in the Pacific Theater where he was wounded at Peleliu and Okinawa. Retired as a Lieutenant Colonel. The former economics professor later served as a U.S. Senator from Illinois. By his personal courage, fortitude and leadership, the Honorable Paul H. Douglas demonstrated the personal traits characteristic of Marine leaders.[1]